Amazing that throughout this entire post there is no mention of the MN3001 as a sub for this circuit. The MN3001 is a dual 512 stage BBD, just like the SAD1024. One of the biggest problems I think people have with subbing in BBDs for the SAD series is they automatically assume the SAD1024 should be subbed with an MN3007. They are completely different in every way, shape and form. It's no wonder people get unsatisfactory to non-working results. Use what is closest to the datasheets and you'll be surprised what can be accomplished....

Agreed.But many don't know how to read a datasheet. They only read that a SAD1024 was replaced by a MN3007. They fail to read that this also requires timing changes. And after all reading it is requested that someone hands the "howto" on a plate.

The MN3001 is hardly a drop in, you need to account for the large insertion loss, the different biasing requirement (+5V back-gate bias) it's also a noisier chip and not to mention, no where near as plentiful in supply as a MN3007, the few out there would probably dry up very quickly if a popular project called for them. The MN3010 while a bit more suitable also suffers from very short supply so neither are good alternatives, that's why they get ignored.

The MN3007 can be adapted to this circuit with minimal effort (if you know what to do) and is easier to source from many suppliers (and allows for easy switching between 3007 & 3207 so that sourcing is even easier as the 3207 is still in production) in fact once the PCBs are drawn and prototyped there'll be a project for doing just that.

larsjm wrote:Amazing that throughout this entire post there is no mention of the MN3001 as a sub for this circuit. The MN3001 is a dual 512 stage BBD, just like the SAD1024. One of the biggest problems I think people have with subbing in BBDs for the SAD series is they automatically assume the SAD1024 should be subbed with an MN3007. They are completely different in every way, shape and form. It's no wonder people get unsatisfactory to non-working results. Use what is closest to the datasheets and you'll be surprised what can be accomplished....

....This is a "dish" on MN3007 it is necessary correctly to prepare All will be OK!

The MN3001 wasn't' being offered as a perfect, "drop-in" replacement that require no work, but rather a more accurate representation of the original circuit, mainly for the second chip running in parallel multiplex. If we're not going for accuracy, why are we bothering to try to clone this thing in the first place? An MN3007 can't run parallel multiplex, nor can an MN3207. And as far as noise, how is the MN3001 inferior? It specs out exactly the same as the SAD1024: S/N of 70db with a THD of <1%...

We're bothering to clone these circuits to have a functional work and sound alike of the original circuit which otherwise we couldn't have anything close to and of course the fun of the build.

If we wanted accuracy then we wouldn't go for an MN3001 any way, we'd all be trying to find a pair of SAD1024s but this way, everyone that wants to should easily be able to build a clone. I very much doubt an audience is going to hear our chips aren't in parallel multiplex

We could run 2 x MN3007 in parallel multiplex... but why bother, parallel multiplex improves the sampling, the 3007 is already a better chip and should theoretically at least, be equal to a SAD1024 in parallel multiplex.

Back on track, going back to the best way to clock the 2 BBDs using 3007s as i'm trying to get my head round it, we have the option of doubling the clock and then using the spare half of the 4013 to divide that back down for the 1024 stage device however... the 1024 is only in play in the Chorus and Slap back modes... so what's wrong with just halving the clock cap for the 512 stage device modes (flanger & filter matrix) and then adjusting the value of the 150pF switched in for chorus & slap back accordingly to account for the now doubled clock on the 512.

Just trying to think of how best to keep it as stock as possible and while i'm sure the answer is in front of me, it's one of those situations where I swear i'm not thinking of something.

Scruffie wrote: We could run 2 x MN3007 in parallel multiplex... but why bother, parallel multiplex improves the sampling, the 3007 is already a better chip and should theoretically at least, be equal to a SAD1024 in parallel multiplex.

Hi Scruffie, any advice on how to go about getting a pair of 3007s to run in parallel multiplex mode? I'm quite curious to try it and compare things to a single BBD.

Scruffie wrote: We could run 2 x MN3007 in parallel multiplex... but why bother, parallel multiplex improves the sampling, the 3007 is already a better chip and should theoretically at least, be equal to a SAD1024 in parallel multiplex.

Hi Scruffie, any advice on how to go about getting a pair of 3007s to run in parallel multiplex mode? I'm quite curious to try it and compare things to a single BBD.

Find the old SAD1024 datasheet, it's described nicely there.

For an example of it in use, I think the BYOC flanger might use the chips in parallel multiplex but that is only from memory.